Rotative winged aircraft



March 28, 1939. V

H. S. CAMPBELL ROTATIVE WINGED AIRCRAFT Filed. Jan. 8, 1937 3 Sheets-Sheet l INVENTOR WM ATTORNEY-5 March 1939- H. s. CAMPBELL ROTATIVE WINGED AIRCRAFT s Sheets-Sheet 2 Filed Jan. 8, 1937 INVENTOR WM ATTORNEY$ March 28, 1939. H. CAMPBELL 2,151,687

ROTATIVE WINGED AIRCRAFT Filed Jan. 8, 1937 3 Sheets-Sheet s INVENZOR BY ATTORNEYS Patented Mar. 28, 1939 UNITED STATES ROTATIVE WINGED' Harris S. Campbell, Willow Grove, Pa., assignor, by mesne assignments, to Autogiro Company of 'America, a corporation oi Delaware Application Claims.

In addition, the invention contemplates improvements in driving and braking mechanisms for an aircraft sustaining rotor, especially as to parts of such mechanisms which are immediately associated with the rotor hub.

More specifically, the invention provides for; a novel disposition of certain internal parts of the hub such as bearings, so as to permit mounting the hub for controllable tilting within a gimbal ring or the like of unusually small diameter. In conjunction with this phase of the invention, the improved structure also provides'a novel arrangement of pivots or trunnions for the gimbal 5 ring and hub, all of which requiresmaller clearances than prior arrangements and therefore result in further compacting of the entire rotor head assembly.

The clearances referred to above have -especial reference to location of certain other parts of the rotor head, such as partsof a driving mechanism adapted for use in initiating rotation of the rotor prior to take oif.

Another object of the invention is related to 5 features of the driving arrangement, according to which the driving torque is transmitted from a driven gear to a hub spindle through an overrunning clutch, the gear and clutch both being located in the plane of a disk which is keyed to 40 the hub spindle. These arrangements reduce irregular bearings and thrust loads and provide for utilization of parts of minimum weight and size. Referring further to the driving arrangements for the rotor, the invention has in view a novel 45 mounting for the driven gear, in accordance with 55 plying a braking torque to the rotor. This ary January 8, 1937, Serial No. 119,575

(Cl. 244-48) This invention relates to rotative-winged airrangement is also of a compact nature and is made readily accessible for adjustment or the like by the employment of a removable casing section incorporated at the bottom of the hub.

How the foregoing objects and advantages are 5 obtained and also others which will occur to those skilled in the art, will be more apparent from a consideration of the following description, referring to the accompanying drawings, in which- 10 Figure 1 is a side elevational view of a rotor head assembly of the character here involved;

Figure 2 is .a horizontal sectional view taken substantially as indicated by the section line 2--2 on Figure l but omitting certain parts for 15 the sake of clarity;

Figure 3 is a vertical sectional view through the rotor hub shown in Figures 1 and 2, this view being taken substantially as indicated by the section line 3-3 on Figure 2; 20

Figure 4 is a vertical sectional view similar to I Figure 3 but illustrating a modified construction;

.post I. The-two posts are joined-at their upper ends and support a pair of laterally and upwardly diverging arms 8-8 (see Figures 1 and 2) forming an upwardly open yoke between which-the rotor. head is nested. A gimbal ring 9 is pivotally mounted between the upper ends of members 8 by means of trunnions llllll. The rotor-hub indicated, generally in Figures 1 and 2 by the reference numeral I l is received in the gimbal ring and extends thereabove as well as-therebelow. The hub is mounted in the ring by means of trunnions l2li, the two pairs of trunnions thus providing for tilting of the hub in all directions in order to effect flight control of the craft substantially in accordance with the disclosure of the copending application oi Juanvde la Cierva, Serial No. 645,985, filed December 6, 1932.

Actual tilting of the hub may be effected by suitable control connections including the control arm ill (see Figure I) mounted on pin it (see Figure 2) and extended downwardly for-connection with a control tube or the like It (see Figure 1) which may be suitably coupled with a pilot's control in the cockpit of the machine. The control connections I6, 14 and 15 are effective to tilt the rotor fore and aft about the axis of trunnions ill-l0. Similar mechanism (not shown) preferably connectedwith some part of the hub itself may be employed for effectinglatera'l tilting of the hub.

As'clearly seen in Figure 1, stop devices including an intermediate member Illa conveniently located' between the forks 8-6 of the mounting yoke, and cooperating spaced abutments llib-I 6b serve to limit fore and aft tilting movement of the rotor hub about the axis of the trunnions lB-Hi.

It will be understood that the craft is ordinarily equipped with an engine and propeller for forward propulsion. The engine may be employed as a source of torque for initiating rotation of the rotor prior to take off from the ground. For this purpose (as seen in Figure 1) a drive shaft I6 is extended upwardly from the body of the craft toward the rotor hub. Toward its upper end the shaft is provided with flexible joints indicated at l1 accommodating the tilting movements of the hub on the control pivots l6l0 and l2-i2.' Further structure of the drive mechanism will be described hereinafter, especially those ports of the mechanism which are immediately associated with the hub spindle.

In order to slow down rotation of the rotor after making a landing, the rotor hub also incorporates brake mechanism, hereinafter described more in detail, the control for which is indicated at 18 in Figure 1.

Still referring to Figure 1, portions of two of the rotor blades incorporated in the rotor are shown at l9, these blades being coupled by means of a drag articulation 26 with an extension link 21 which, in turn, is coupled by means of a flapping articulation 22 to pairs of apertured ears 26 at the top of the rotor hub.

Referring now particularly to Figure 3, it will be seen that the apertured lugs or ears 23 are formed at the top and as a part of the rotative hub spindle 24. This spindle is journaled in a housing having a relatively narrow neck portion 25 and a lower and larger diameter casing part 26.

As already mentioned, the control pivots 'or trunnions |2-|2 mount the hub casing for tilting movement within the gimbal ring 6. These pivots are clearly shown in Figure 3.

A pair of spaced bearings is interposed between the rotative'spindle 24 and the cylindrical cavity in the neck or small diameter part 25 of the housing. The lower one of these bearings includes an inner race 26 and an outer race 21 with rolling elements such as balls 28 therebetween. The

thrust of sustentation is transmitted from the lower end of the rotative spindle 24 through the removable nut 29 and sleeve 66 to the inner race 26 of the lower bearing. From this point the thrust is transmitted through the spacing sleeve 3| upwardly to the inner. race 62 of the upper bearing, from which it is carried through the balls 33 thereof to the outer race 64 and from thence to the shoulder 35 at the top of the hub housing. An

external shoulder 66 is provided adjacent the up per end of the rotative spindle part 24 proper and serves as an abutment or reaction point for the nut. 29, which latter thus tightens all of the intermediate members in position.

An additional sleeve 61 fitting the inside diameter of the housing part 25 is provided, this sleeve being fastened in place as by bolts 66 and being of such axial dimension as to leave a small clearance 69 adjacent the outer race 21 of the lower dered part 12 of the housing.

bearing. This arrangement materially simplifies assembly, fitting and the like of the bearing parts and associated spacing sleeves, etc., particularly since it eliminates the necessity for machining of various parts to within close tolerance figures. A further advantage of this arrangement is that in the-event of failure of the upper bearing, the lower bearing will assume the thrust.

Referring now to the drive mechanism, the shaft l6 hereinbefore referred to, is adapted to be coupled (through the flexible joints 11 shown in Figure 1 with the pinion shaft 46 carrying pinion The shaft is provided with bearings 42--42, both of which are mounted in the housing of the hub and which are located one at either side of the plane of rotation of the pinion. The pinion, in turn, meshes with a driven ring gear 46 which has a bearing, composed of rolling elements 44, mounting it on a race 45 carried by the .as a part of the sleeve 66 which, of course, is keyed to the spindle 24 as at 46.

The disk 46 is also provided with a cylindrical part 49 having a braking surface thereon for cooperation with brake shoes 56, suitable friction material 5| being interposed therebetween. The brake shoes are mounted on the casing part 52 generally of dish shape which is secured to the asing part 26 by bolts 56 and which is removable downwardly to permit access not only to the brake parts but also to elements of the drive mechanism.

At the extreme lower end of the spindle 24, a gear 54 is mounted in position to cooperate with a pinion 55 carried on a shaft 56 projecting downwardly through the casing for connection with a flexible shaft mounted in sheath 51 (see Figure 1. This structure is employed to actuate a tachometer giving rotor speed readings.

Figure 4 is a view similar to Figure 3 illustrating a, modified form of certain features of the rotor hub. In this form the narrow part of the hub housing 55 surrounds a rotative hub spindle 56 having a flanged plug 66 threaded into the lower end thereof so as to position and secure bearing parts interposed between the spindle and housing. These parts are of modified arrangement and include the sleeve 6|, a lower radial bearing having an inner race 62', a spacing sleeve 63, a thrust bearing having an inner race 64, the outer race 61 of this bearing and the outer race 68 of an upper radial bearing. The outer races 66, 6 1 and 66 (bottom to top) fit the inside diameterof the cylindrical part of the hub housing 56. An annular member 66 fastened in place by bolts 16 serves to position the outer races 61 and 66 of the thrust bearing and the upper radial bearing. Clearance is provided between the inner race 65 of the upper radial bearing andthe immediate subjacent thrust hearing as at II and in view of this arrangement the thrust of sustentation is transmitted from the rotative spindle 56 upwardly through the sleeve 6|, the inner race 62 of the lower radial bearing, the spacing sleeve 66, the inner race 64 of the thrust bearing and through this bearing to the outer race thereof, from which the thrust is carried through the outer race 66 of the upper radial bearing to the shoul- The foregoing bearing arrangement thus provides for the carrying of the thrust load in one form, in that it comprises a plain bearing bushing driving parts.

bearing, using the remaining bearings for radial loads only during normal flight.

The collar GI serves to carry the disk or annular member 13 which, similarly to the drive arrangement described in connection with Figure 3, c0- operates with the overrunning rollers ll which are surrounded by the ring gear I5.- Ihe supporting bearing for the gear "I! is of modified 16 instead of the balls ll employed in the arrangement of Figure 3. In both cases, however, it will be noted that the ring gear is journaled on, the non-rotative housing part substantially independently of the associated overrunning clutch.

As in the arrangement already described, a pinion ll cooperates with the ring gear to drive the same.

The member 13 in the form of Figure 4 also carries a cylindrical part II serving as a brake drum in cooperation with the brake shoes or equivalent braking means I9. Here again, the internal brake parts are mounted for removal with thelower casing part ll which cooperates with the housing or casing part 8! of the hub to form a .complete enclosure for the brake and A connection shaft 82 tapped into the plug Gil at the bottom of the rotative spindle 59 may be employed as a drive take-ofl for the rotor tachometer.

Toward the right of Figure 4 it will be noted that the hub casing part II is equipped with an eye 83 to which a control tube or lever may be attached and extended downwardly into the cockpit of the machine for eilfecting tilting movements of the hub to control the craft in flight.

The modified form of Figure 4 also incorporates a different arrangement of gimbal ring and tilting pivots. One of two laterally aligned trunnions is shown at 84, these trunnions serving to mount the rotor hub proper within the gimbal ring 85 for tilting movement fore and aft of the craft. The gimbal ring, in turn, is mounted by means of trunnions -46 for tilting movement with respect to fixed supporting elements 81-41, and this gimbal ring arrangement is, therefore, inverted with reference to the structure of Figure 3. The form of Figure 4 will be found to be preferable in cases where fixed supporting elements for the hub may most conveniently be brought to the gimbal ring at points in front of and to the rear of the rotor hub, in contrast with the arrangement previously described (see particularly Figures 1 and 2) wherein the fixed supporting elements are-brought up at the sides of the lustrated in Figure 5. Here the arrangement is quite similar to that of Figure 2 although the gimbal ring 9a only partially surrounds the rotor hub, there being a pair of laterally positioned trunnions ill-Ill as in Figure 2 but only a single trunnion l2.

This single trunnion, however, is located in front of the hub, and is therefore positioned close to the location of the rotor thrust line which in normal flight moves forwardly of the rotor axis line.

The arrangements of Figures 1, 2, 3 and 5 as to the'gimbal ring mounting are especially advantageous from the standpoint of simplicity of parts and also because the fore and aft and lateral tilting trunnions are so related tothe gimbal ring as to substantially eliminate the necessity for vertial clearance between the top of the portion of the housing surrounding the driving pinion 43 and the underside of the gimbal ring, there being no relative vertical movement between these parts at the point where the drive is .brought up to the hub. The arrangements of Figures 1, 2, 3 and 5 is further of especial advantage in providing an overall external shape which is relatively easily faired to a streamlined contour.

In all forms illustrated the gimbal ring arrangement and the various parts including the bearings, etc. of the hub proper areso relatively located that a gimbal ring of relatively small overall diameter may be employed. It will be noted that the hub incorporates an upper fitting for attachment oi blades which is of substantial overall diameter and a lower housing for en-, closing the driving and braking parts, between which upper fitting and lower housing there is provided a relatively narrow neck. The gimbal ring lies in such a horizontal plane as to surround this narrow neck.

The arrangement of the ring or trunnion gear within the hub of both forms is of particular advantage because of several factors including the simplicity of the parts, the direct transmission of drivingthrust through the plane of the supporting disk for the over-running clutch, and the mounting of the trunnion gear on a bearing carried by the housing independently of the overrunning clutch.

Maximum accessibility of the driving and braking parts is also provided for, since the lower casing part of the hub may readily be dropped, thus withdrawing the'brake parts and also exposing driving parts.

I claim:

1. For an aircraft having a sustaining rotor,-

a rotor head assembly including a rotative hub spindle, means for pivotally attaching the blades of the rotor to the upper end of the spindle, a supporting housing surrounding a lower portion of the spindle, a pair, of bearings between the spindle and. housing spaced axially thereof, a driven gear secured to the spindle below the lower of said bearings, a cooperating driving gear journaled in the housing adjacent the driven gear, an overrunning clutch between the driv en gear and the spindle, and a bearing mounting the driven gear on the housing and serving to transmit bearing loads to the housing substantially independently of the overrunning clutch.

2. In a hub structure for an aircraft sustaining rotor, cooperating rotative and non-rotative hub parts the latter of which serves as a bearing support for the former, a driven gear for the rotative part, an overrunning clutch between said gear and said part, and a bearing mounting said gearon the nonrotative part.

3; In a hub structure for an aircraft sustaining rotor, cooperating rotative and non-rotative hub parts the latter of which serves as a bearing support for the former, 'a brake drum including disk and cylindrical portions secured to the rotative part of the hub, means cooperating with the cylindrical portion of the drum for applying a braking torque to the rotative part, driving means for the rotative part including a driven gear and an overrunning clutch interposed between the gear and the disk portion of said drum substantially in the plane thereof, and a bearing for mounting said gear on the nonrotative part of the hub.

4. In an aircraft sustaining rotor hub structure, an internal rotative hub spindle, a surrounding supportlng housing, a pair of axially spaced bearings between the spindle and housing, each of said bearings including inner and outer races with rolling elements therebetween, means for transmitting the thrust of sustension from said spindle to the inner race of the lower a bearing, means for transmitting said thrust from the inner race of the lower bearing to the inner race of the upper bearing, and means for transmitting said thrust from the outer race of the upper bearing to the housing, the outer race of the lower bearing being axially positioned only by its cooperation with the associated rolling elements.

HARRIS S. CADLPBELL. 

